Pope Alexander II’s endorsement of William the Conqueror’s invasion of England in 1066 may have been influenced by a papal power struggle, according to new research by Tom Licence, a professor of medieval history and literature at the University of East Anglia. The Norman conquest, culminating in the Battle of Hastings on October 14, 1066, has traditionally been understood as a contest between William and Harold Godwinson over the English throne following the death of Edward the Confessor. However, Licence’s findings suggest that the conflict also intersected with rival factions vying for control of the papacy.

It has long been recognized that Pope Alexander II sanctioned William’s expedition by allowing his papal banner to accompany the Norman forces as they crossed the English Channel. The prevailing explanation held that Alexander supported William because Harold broke a sacred oath to back William’s claim and because the pope sought ecclesiastical reform in England. Yet, letters from the pope to William surviving in later canon law compilations reveal more personal motivations rooted in the spiritual and political divisions of the era.

In a letter dated between 1066 and Alexander’s death in 1073, the pope described the English people as having turned away from “the path of truth” under the influence of a malevolent leader “fired with the pride of Satan.” Licence interprets this as a veiled reference to Harold’s political allegiance during a contemporaneous contest for the papal throne. In 1061, two rival popes were elected: Alexander II and Bishop Cadalus of Parma, known as Honorius II. For several years, supporters of both factions fought for control of Rome and the broader Christian world, with Honorius backed by the Holy Roman Empire and influential supporters in northern Europe.

Licence argues that Harold Godwinson aligned himself with Honorius II, effectively opposing Alexander II, who had then granted his blessing to William’s invasion in part as a response to this challenge. The pope’s condemnation of the English ruler as an enemy of God’s covenant suggests a deeper religious and political dimension underpinning the conquest. “If Harold had aligned England with Alexander’s rivals, it would explain why the pope was willing to support the overthrow of a crowned king,” Licence stated.

David Fergusson, a professor of divinity at the University of Cambridge, who was not involved in the research, noted that the work provides “a fresh perspective on the wider political currents that contributed to the events of 1066.” The findings invite a reevaluation of the Norman conquest, emphasizing the complexity of alliances and conflicts not only within England but across the broader medieval Christian world.